Tuesday, August 23, 2011

Lessons from the Mock Up

     I made quite a bit of progress in the shop today and wanted to go back out tonight but the thermometer scared me off!  Really glad there's not a tight deadline on this project and it helps that my client is a "car guy" so knows only too well what it's like working in our desert heat.  Last night I almost had the mock up complete and if there's one thing I've learned it's that the tolerances/clearances in a barrister bookcase leave very little room for error.  There is a type of complicated mechanism that looks somewhat like a scissor jack and is supposed to control the travel in the door by keeping it parallel.  I haven't read too much positive about that system other than it's very tricky to make, install, and keep running smoothly.  I suppose that a barrister type arrangement is suitable for what it's designed for; occasional access.  Drawers are designed for frequent opening and closing so their design is totally different.
     Anyway, here's a few pictures of what's been done to date:
Door Close Up
Here you can see the groove that the pin will ride, this is the heart of how this works.  What's critical is that there is a minimum of play between the end of the pin and the wall of the groove.  I'm using brass rod for the pin.  Once the cabinet is assembled, I'll need to design a molding that will cover that groove and also prevent the door from coming out.  The door will be installed through the back of the cabinet before the knobs are attached.  Once all of the doors are installed the back is screwed on.  Should it ever be necessary to remove a door, the back can be unscrewed, knobs removed, and then it will be removable.  Not something you ever want to do but you need to leave yourself an exit plan!

Over-all View of Mock Up, Plans, & Parts

Here's another view of the mock-up with the plans behind it.  As you can see, this will be a fairly tall unit.  You'll notice the middle section of the case is considerably larger than the others.  This is where the turntable will be housed.  The lines drawn on the door were to give me a visual for determining the width of the stiles.  Turns out that 1 3/4" looked about right!

 The last major bit of work completed today was to cut all of the pieces required for the doors.  They've all been brought to a uniform thickness with the planer but I always surface each one with a hand plane (#4 Smoother).  In my opinion, a machined surface just doesn't compare to what you can achieve with a good, sharp hand plane. The coping cutter is set up on the shaper so that's where we'll start tomorrow.  A good practice is to make extra pieces which I did. Oak can split pretty badly when you use a shaper or router on it, it seems to never fail that if I make a few extra pieces at this time I won't need them.  If I take a chance and fail to make extra stock I have a problem and have to start from scratch -- isn't that Murphy's Law?

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